Shooting Super 16 with 35mm Zeiss super speeds. The guy at
the rental house is telling me 35mm lens double in focal length
if used on super 16mm cameras. I've done this a couple of
times before and I don't remember the focal length doubling.

He's saying that since 35mm lenses are made to cover twice
the area of Super 16 all of the light is focused on the half
side of the frame, and that it doubles the focal length…which
does make sense, but I've never heard that it does that.

It does make sense though.

Tenolian Bell
Cinematographer NY

Tenolian Bell wrote :

>The guy at the rental house
is telling me 35mm lens double in focal >length if used on
super 16mm cameras.

Change rental houses.

A 50mm lens = a 50mm lens, no matter what format you're shooting,
as long as it covers.

Note that the field of view of a 50mm lens on 35mm will be
significantly wider than the same lens used on a 16mm camera,
but a 35mm-format 50mm lens will have the same field of view
as a 16mm-format 50mm lens.

This has been discussed many times here, and, really, it's
kind of amazing that people still make statements like this.

Perhaps he meant to say something slightly different, like
"a 25mm lens is 'normal' (whatever 'normal' means) on
a 16mm camera, and a wide angle on a 35mm camera?

But the focal length remains the same -- 50mm = 50mm.

Jeff Kreines

Wrong! A 50mm is a 50mm is a 50mm that's all there is to it.

This is a common misperception.

50mm on 16 looks longer(tighter) than it does on 35. However
it makes no difference if the lens covers 35mm frame or not.

If you compare a 16mm 50mm lens to a 35mm 50mm lens they will
have the same field of view.

I actually had to prove this to a "DP" once at prep.

Bret Lanius

Try this, put up a 25mm focal length for super 16, mark the
framed area, now out up a 25mm for the 35mm format' now compare
the two image area.

Stacy Strode

Tenolian

I'd really like to know what guy, and at what camera rental
house here in New York told you this.

Either you heard him very wrong or he seriously should not
be working at a professional motion picture camera rental
facility.

Mitch Gross
NYC DP

The thing that makes me laugh (or cry) about this the most
is that it took place at a camera rental house, where it would
have taken all of two minutes to prove the guy wrong.

Mitch Gross
NYC DP

>The guy at the rental house
is telling me 35mm lens double in focal >length if used on
Super 16 cameras.

As someone who spent his first two years, seven months, a
week and two days working in a rental house, I can tell you
authoritatively that :

A/. This guy doesn't know what he is talking
about and you should find someone else at the rental house
to deal with--or a different rental house.

B/. In the manner of many jerks he is talking
confidently about something that he has not learned from actual
experience or from people who actually know what they're doing.
If he had any common sense he would have subjected this idea
to some physical testing, though a simple 'thought experiment'
ought to clear it up. Maybe that was too much work and it
was easier to just pronounce things without verifying them.
I am awfully tempted to suggest he has missed his chance to
work in the current White House, where this style of reasoning
and discourse is quite popular, but that would be getting
into politics, which I know Geoff frowns on, and quite rightly
too.

C/. Unfortunately the rental house environment
can occasionally create such monsters, people who confuse
a certain isolated knowledge of camera equipment with knowledge
of cinematography. Sometimes people like this go out and become
camera assistants. They are recognizable because they're the
ones who insist that production wait while they check the
f-f depth--again. Later on they get to wait--by the phone.

50mm is 50mm, whether Primo for 35, or Zeiss SS for 16.

However, 50mm renders a different *image size* on 35mm than
on 16, or for that matter on 35mm still, or on 4x5, or VistaVision,
or whatever.

What he might have heard about--and misunderstood--was that
if you want the effect of a 50mm in 35mm, but are shooting
16, you will get (roughly) the same effect with a 25mm. (Super
16 will be the same vertically but obviously wider horizontally.)

It's not that hard.

Or maybe I've been wrong all these years and it actually IS
rocket science?

Alan Thatcher
DP
Chicago

>As someone who spent his first
two years, seven months, a week and >two days working in a
rental house, I can tell you authoritatively that :

I meant first two years (...) IN THE BUSINESS … I haven't
been around THAT long.

Alan Thatcher

Alan Thatcher wrote :

>I am awfully tempted to suggest
he has missed his chance to work in >the current White House

Or, as they say, Faith-Based Focal Lengths...

Jeff "like a prayer" Kreines

Tenolian Bell wrote :

>He's saying that since 35mm
lens are made to cover twice the area of >Super 16, all of
the light is focused on the half side of the frame, and that
>it doubles the focal length, which does...

Which does..... exactly what?

It doesn't double the focal length. It just gives the lens
greater covering power, and, of course, when you're dealing
with wider lenses it's harder to make them cover a larger
aperture, which means a 10mm lens that covers the 35mm cine
aperture costs more than a 10mm lens that only has to cover
16mm.

Jeff Kreines

So after all this. If you use 35 lenses on S16 it remains
its original length. Fine, but is there a direct formula to
the general rule that 16m lenses are tighter then 35 lenses.
Does it fluctuate as it goes up and down or is there a constant?

In other words. If I shoot a 10mm on 35 I would need 6mm in
a 16 lens (ballpark) to achieve the same distortion, field
of view, etc. Does that same ratio apply to wider and longer
lenses or does it fluctuate?

Chris Sargent

The relative relationship is constant. I must say I'm continually
amazed at the professionals who have trouble with this. It
has to be the single most misunderstood concept in the industry
right next to how the DVX100 records 24p onto 60i. Amazing.
Next thing you know someone will tell me that there are no
magic imps at the lab making all the pretty pictures. I know
they're there--I've seen them (and they're often union)!

Mitch Gross
NYC DP

The shoot is in LA. Actually this is at a well known rental
house based in NY, but has a office in LA. This rental house
has a great deal of experience with super 16. I haven't met
the guy, I put the order in to the producer. The producer
calls me back and tells me this is what the guy at the rental
house told him.

This rental house has a great deal of experience with super
16 and I didn't really feel like calling the guy and arguing
with him. But before I did I wanted to make sure I'm not the
crazy one.

I may or may not have time to mount lens' on the camera to
prove him wrong. So what should I tell him when ever in inevitably
speak to him?

Tenolian Bell

>The producer calls me back and
tells me this is what the guy at the >rental house told him.

>I may or may not have time to
mount lens' on the camera to prove him >wrong. So what should
I tell him when ever in inevitably speak to him?

Tell him that your producer clearly did not understand what
he was told and that it made for a fun short thread on the
CML. I'm sure that the guy read it himself on the list and
thought, "I wonder who it was that could say such a dumb
thing." Little did he know it was himself and there was
just a moron (read: producer) who translated the message completely
incorrectly. I'm sure everyone on Willow Ave. had a nice laugh.

Mitch Gross
NYC DP

Is there a formula or ratio, to sort this out for me and the
imps.

Chris Sargent
Dir/DP
Toronto

Jeff Kreines writes :

>This has been discussed many
times here, and, really, it's kind of >amazing that people
still make statements like this.

Yes, and I like the way Jon Fauser puts it - if you're using
35mm format lenses(Motion picture or stills ones for that
matter)on a 16mm camera, you're just carrying "extra
glass" around.

Worthy of discussion is the "sweet spot" as some
people call it - Is it worth it to use 35 mm format lenses
in 16mm because the back element is much wider, or is it because
more R&D goes into the 35mm format lenses?

My 50mm Contax converted to Aaton mount has a much wider rear
element than a motion picture 50mm 35mm format Zeiss-but I
know there's more to this and I think manufacturers don't
necessarily want a wide rear element-could someone post about
35/16 lens resolution once again?

I believe some of it has been covered before.

Best regards,
John Babl
Miami

In theory a lens that is designed only to cover a 16mm (or
Super-16) gate area can achieve a greater resolving power
than a 35mm lens because it doesn't have to jump through as
many hoops. A lens that covers 35mm needs to try to keep sharpness,
brightness, reticular distortion and chromatic distortion
to a minimum all the way to the corners of the frame. In keeping
the corners acceptable there are a number of compromises that
lower these same qualities to some degree in the frame centre.
A lens for Super-16 has a much smaller area to deal with so
doesn't have to compromise as much.

That of course, is just theory. In practice the R&D that
goes into 35mm format lenses is far greater than 16mm glass,
so the performance factors between these lenses is near identical
if not better within the Super-16 frame. This can be tested
easily by measuring MTF, shooting some chart tests and simply
putting up the lenses on a common lens projector at any decent
rental house. I really recommend every DP pay a visit to the
back room at their local rental house and take a look at some
lenses on a projector. So many characteristics that are discussed
here and in various books become instantly visible and clear
when projected in front of you.

Mitch Gross
NYC DP

John Babl wrote :

>but I know there's more to this
and I think manufacturers don't >necessarily want a wide rear
element-could someone post about 35/16 >lens resolution once
again?

Sometimes, with a lens that casts too large a cone of light,
and isn't masked, you'll get light bouncing off parts of the
camera that light doesn't normally strike, and it can either
lower contrast or introduce artefacts.

I've had this happen in optical printers.

Jeff Kreines

Jeff Kreines wrote :

>Sometimes, with a lens that
casts too large a cone of light, and isn't >masked, you'll
get light bouncing off parts of the camera that light >doesn't
normally strike, and it can either lower contrast or introduce
>artefacts.

I use some 35 mm lenses on my Mitchell Reflex 16 when doing
time lapse. Yes they can induce artefacts because they are
spraying light all over the place as compared to a 16 lens.
And this is with a camera that has a pretty light tight shutter
compared to an Aaton or SR or any other non focal plane shutter
camera for that matter. Be careful especially with light sources
especially as they get towards corners of
the frame.

Mark Smith
Oh Seven Films
143 Grand St
Jersey City, NJ 07302

Chris Sargent writes :

>...is there a direct formula
to the general rule that 16m lenses are tighter >then 35 lenses.
Does it fluctuate as it goes up and down or is there a >constant?

To rephrase as simply as humanly possible what others have
been saying, let's assume you're shooting a picture of a barn.

1) A lens of
X focal length lens will always project an image of the barn
at Y size on the image (film) plane.

2) 16mm film,
being smaller than 35mm, receives a smaller portion of that
projected image. So the 35mm frame might include the whole
barn, but the 16mm frame will include only the barn's door.

3) The size ratio of 35mm to
16mm is constant, therefore the 16mm film will always capture
the same fraction of the 35mm image.

I hope that tells you what you need to know.

(For the sake of getting the principle across I've left out
some niceties such as variations in aperture size (Super-16,
Super-35, Academy, etc.) and things like the overall size
of the projected image, which might make a lens designed for
a 16mm camera fail to project an image large enough to fill
a 35mm frame, resulting in vignetting.)

I imagine that the original confusion arose because people
often say "focal length" when they mean "angle
of view." So when you mount a prime lens intended for
a 35mm camera on a 16mm camera, its focal length stays the
same... but the resulting angle of view gets narrower.

Dan Drasin
Producer/DP
Marin County, CA

Jeff Kreines writes :

>Sometimes, with a lens that
casts too large a cone of light, and isn't >masked, you'll
get light bouncing off parts of the camera that light >doesn't
normally strike, and it can either lower contrast or introduce
<artefacts.

And this is why the Optex lens mount adapter for using Nikon
35mm still lenses on an Aaton has a small rear pupil with
the inside painted matte black. I've also seen on some converted
Contax lenses a metal disc that limits the exit pupil of the
lens. My Contax lenses do not have this and have never been
a problem.

Mitch Gross
NYC DP

Mitch Gross wrote :

>I really recommend every DP
pay a visit to the back room at their local >rental house and
take a look at some lenses on a projector. So many >characteristics...become
instantly visible and clear when projected in >front of you.

I would back that firmly. Last September when I had a problem
with flare on a Canon 8-64 (or was it the 7-63, have to look
at my notes) had checked for 4 of these in the optics room
of the rental place and the differences within the same make
and type of lenses was just unbelievable. Fall off in the
corners, tracking, breathing, definition of the horizontal
lines vs vertical lines. Amazing the differences.

This becomes even more visible with not so young lenses and
rental ones. Especially in the 16 mm size as far as I was
told 16mm lenses no longer are being developed for economical
reasons. It is worth to pay a visit and see for oneself these
tests.

Regards
Emmanuel from Munich

Interestingly enough a different question was asked on how
to calculate the angle of view for a 2/3 chip camera. Same
Issue. I provided a quick little flash app that lets you calculate
this.

>1) A lens of
X focal length lens will always project an image of the barn
>at Y size on the image (film) plane.

>2) 16mm film, being smaller than 35mm,
receives a smaller portion of >that projected image. So the
35mm frame might include the whole barn, >but the 16mm frame
will include only the barn's door.

Reply :

So to sum up, lenses are the same whether they’re fitted
to a 16mm or 35 mm camera. 14mm is still a 14mm, no matter
if there is more glass in a larger barrel to suit the size
of camera. Its the film were ultimately exposing so we compensate
with a wider lens...to open up the space for the smaller area
of neg. Simple. Sorry bout that. Hope I'm following. Feel
free to kick me when I'm down.

Chris Sargent
Dir/DP
Toronto

Dan Drasin wrote :

>2) 16mm film,
being smaller than 35mm, receives a smaller portion of >that
projected image. So the 35mm frame might include the whole
barn, >but the 16mm frame will include only the barn's door.

I'm going to assume here that the change from 35mm to 16mm
did nothing to change the relative "distortion"
of the barn door. If you shoot a person in close up on a 24mm
lens in 35mm format their nose will seem larger than it would
to the human eye. (As an aside, this is what I think people
mean when they say a 40mm-ish lens in 35mm format approximates
what the human eye will see...the distortion of and relationship
between objects will be about the same as what we see normally).

Now if you try to shoot the same close up shot in 16mm you
would need to step back a bit to get the same elements in
the shot, no? But what if you couldn't because of a wall behind
you? You'd have to change to a wider lens. Having changed
to a wider lens the person's nose would seem even larger by
comparison with the rest of their face.

Would it be fair-ish to say that if one is shooting in closed
quarters, the 35mm format is a better choice as far as minimizing
distortion?

Piotr Jagninski
Gaffer / NYC

Piotr Jagninski wrote :

>...If you shoot a person in
close up on a 24mm lens in 35mm format >their nose will seem
larger than it would to the human eye...

You're a bit confused here. Perspective is determined only
by distance, not the lens. The wide angle lens simply allows
you to shoot closer and still get the object in the frame.
So, for example, if you shoot a person CU with a 24mm lens
on 35 still camera and compare it with another shot made from
the SAME distance with a 50mm lens, the perspective will be
the same. The difference will be that with the 50mm you couldn't
cover as much of the subject, but what you did get would have
identical perspective.

>...Now if you try to shoot the
same close up shot in 16mm you would >need to step back a bit
to get the same elements in the shot, no?

No, you change to a shorter lens that has the same proportionate
focal length. If on the 35 mp camera you used a 40mm lens,
on a 16mm film camera you'd use a 16mm lens. Both cameras
would see the same angle of view from the same distance, yielding
the same perspective. (Assuming full aperture, 1:33.) The
math: diagonal of the 35mm full aperture is 31mm. 40mm equals
1.29 x 31. Diagonal of the 16mm aperture is 12.5mm. 12.5 x
1.29 = 16.

>you would need to step back
a bit to get the same elements in the shot, >no? But what if
you couldn't because of a wall behind you? You'd have >to change
to a wider lens.

Wade Ramsey writes :
>No, you change to a shorter lens that has the same proportionate
focal >length.

In this particular context a wider lens and a lens of shorter
focal length would be the same thing. All else being equal,
if you're backed up against a wall you zoom out or use a wider
(=shorter focal-length) lens. Or am I missing something?

Dan Drasin
Producer/DP
Marin County, CA

If we're not too overwhelmed by this discussion of "normal"...I'd
like to add that I thought that "normal" had more
to do with magnification and not so much angle of view. This
is what I remember from studying pin hole photography.

This can be demonstrated with a view camera. If you look at
the back focusing plate or ground glass on a 5x7 or 8x10 view
camera the view or size of objects provided by the "normal"
lens will be the same (to your eye) if you move the camera
aside.

But now... as I think about this I don't know how it applies
to 16 or 35, but you have to admit it sounds pretty good and
anyway somebody can use this to take this discussion further...
if anybody wants to.

Edwin Myers
Atlanta dp

Dan Drasin wrote :

>In this particular context a
wider lens and a lens of shorter focal length >would be the
same thing. All else being equal, if you're backed up >against
a wall you zoom out or use a wider (=shorter focal-length)
lens.

No, in this context they aren't. A wide angle lens is a lens
whose focal length is shorter than the normal lens for that
format. In this instance we're talking about changing formats
and using a lens that is proportionately the same, so their
fields of view are identical. One is not wider than the other.
But the 16mm camera lens is shorter than the 35mm camera lens.
(In the example that was quoted, both cameras were using slightly
wide lenses, but neither was wider than the other on its respective
format, so calling the shorter one a wide angle lens in contrast
to the other is misleading.)

>DD : In this particular context
a wider lens and a lens of shorter focal >length would be the
same thing. All else being equal, if you're backed >up against
a wall you zoom out or use a wider (=shorter focal-length)
>lens. Or am I missing something?

Wade Ramsey writes :

>WR : No, in this context they
aren't. A wide angle lens is a lens whose >focal length is
shorter than the normal lens for that format. In this >instance
we're talking about changing formats and using a lens that
is >proportionately the same, so their fields of view are identical.
One is not >wider than the other. But the 16mm camera lens
is shorter than the >35mm camera lens.

And now a word on behalf of rental houses everywhere. Pretend
you're a busy rental guy and a very busy producer calls up
to ask you that question and wants a simple answer immediately
-- one that he can understand, when he doesn't understand
any or most of the terms -- so he can pass the answer on to
his DP, who for some reason doesn't know the answer and cannot,
or will not, call the rental house directly.

So the producer then tells the DP what he thinks the rental
guy told him as the producer understood or misunderstood it.
The question then gets posted here and the rental guy gets
blamed.

Just because someone understands something, it doesn't mean
he or she can explain it clearly. As evidence, I could cite
any number of computer manuals.

In any event, if it is extremely difficult for experienced
professionals to put these essentially visual concepts into
words so that other experienced professionals can understand
them clearly, imagine what it's like when the people involved
are not very experienced and in a hurry and get the info second
or third hand.

One other thing to keep in mind: while we might like people
to think otherwise, rental companies are not repositories
of all knowledge relating to cinematography. If they were,
we wouldn't need cml -- and Geoff Boyle would have to find
something else to do to keep himself up at night.

Brian Heller
IA 600 DP

Edwin Myers writes :

>If you look at the back focusing
plate or ground glass on a 5x7 or 8x10 >view camera the view
or size of objects provided by the "normal" lens
>will be the same (to your eye) if you move the camera aside.

That would be true only if you'd held the ground glass at
a particular distance from your eye. But what distance would
that be? The same as the focal length of the normal lens?
Closer? Farther? Arm's length? ???

Dan Drasin
Producer/DP
Marin County, CA

Dan Drasin writes :

>That would be true only if you'd
held the ground glass at a particular >distance from your eye.
But what distance would that be? The same as >the focal length
of the normal lens? Closer? Farther? Arm's length? ???

Normal distance, of course.

Brian Heller
IA 600 DP

The idea of "normal" or "standard" in
the case of still photography assumes that a "standard"
sized print will subtend the same angle of view, and show
the same perspective, as the original image. .

For prints & enlargements, it's assumed that you would
be using viewing at normal reading distance (darn it there's
that word 'normal' again - say around 16-18 inches or 40-45cm).
I guess the same would be assumed when looking at the ground
glass plate in a plate camera.

The geometry turns out to show that the "normal"
taking lens in such a situation would have the same focal
distance as the viewing distance.

By this argument you need to examine a 35mm negative shot
with a 50mm lens from a distance of 50mm (not so easy) - or
blow it up by a factor of 8 so the print subtends the same
angle at a distance of 8 times as far - or 40cm, the normal
reading distance. This would give you a print of 192mm x 288mm
- about 7 1/2" x 11", twice as big as the "normal"
postcard-sized print.

But the same argument leads us to a 400mm lens for a plate
camera - seems far too long. Typically I'd have expected about
a 250mm lens for a whole-plate camera.

So I guess the whole theory is shot!

Dominic Case
Atlab Australia

Dominic Case wrote :

>...But the same argument leads
us to a 400mm lens for a plate camera - >seems far too long.
Typically I'd have expected about a 250mm lens for >a whole-plate
camera.

Good grief, Dominic! Do they still use the term "whole
plate" in Oz? That's 19th Cent. terminology! But then...

If I recall the history, a whole plate would be something
in the vicinity of 20cm x 25cm or so (about 8" x 10",
to us colonials.) The normal lens for that size format isn't
400mm, it's 325mm, about 13 inches. You can easily view a
contact print from that format and you'll probably automatically
hold it about 30 cm to 40 cm (12" to 16") away from
your eye. So you're going to naturally view it at about the
focal length of the taking lens, the theory still holds.

>...In any event, if it is extremely
difficult for experienced professionals to >put these essentially
visual concepts into words so that other >experienced professionals
can understand them clearly, imagine what >it's like when the
people involved are not very experienced and in a >hurry and
get the info second or third hand...

I'm know Brian isn't defending ignorance of equipment and
processes on the part of anyone working as a professional,
but rather expressing the frustrations of a rental guy trying
to convey technical info to some intermediary who may have
all the techno-savvy of his 6 yr. old daughter. It's obviously
difficult when you have to communicate it to an unqualified
person. You don't explain all this to the intermediary, you
tell him/her, "use this lens." It may well be that
this person can't even adequately describe the problem you
are to help him solve.

But here we're discussing the matters with professionals,
the guys and gals who are directly responsible for producing
the results. They're the ones who, if they haven't had occasion
to learn it before, come to CML to fill in the gaps in their
knowledge. Understanding the theory makes it much easier to
solve future problems that differ somewhat from the one at
hand.

Anyone working with cameras needs to understand the relationship
of the lens focal length to the camera's format and how that
in turn relates to scene coverage. It's more vital than ever
before, because we are now dealing with S-16, 35 in several
iterations, 2/3", 1 /2" , 1/3" and even smaller
video. We have more formats than ever before and in many cases
we're called on to choose between them for a project. We'd
better know how that impacts lens choices.

And don't send a dodo to the rental house (even in Oz!) That's
like sending my totally computer challenged wife to Microsoft
for help.

>That would be true only if you'd
held the ground glass at a particular >distance from your eye.
But what distance would that be? The same as >the focal length
of the normal lens? Closer? Farther? Arm's length? ???

I think that will be true if you view the ground glass at
the focal length of the lens you're using. You can do that
with large format cameras. With shorter lenses you'd view
it closer, ultimately needing a magnifying glass to focus
on the close viewing distance; longer lenses, farther away
from the ground glass.